This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A268047 #5 Jan 25 2016 10:51:20 %S A268047 4,159,9054,467899,22309009,999810316,42764566838,1764109373799, %T A268047 70707661248442,2768685594929370,106349114580207849, %U A268047 4020025709583200998,149916029504065737481,5526692782368686983855,201739654709622213459404 %N A268047 Number of nX3 0..3 arrays with every repeated value in every row unequal to, and in every column equal to, the previous repeated value, and new values introduced in row-major sequential order. %C A268047 Column 3 of A268049. %H A268047 R. H. Hardin, <a href="/A268047/b268047.txt">Table of n, a(n) for n = 1..210</a> %H A268047 R. H. Hardin, <a href="/A268047/a268047.txt">Empirical recurrence of order 78</a> %F A268047 Empirical recurrence of order 78 (see link above) %e A268047 Some solutions for n=5 %e A268047 ..0..0..1....0..0..1....0..0..1....0..0..1....0..0..1....0..0..1....0..0..1 %e A268047 ..0..0..2....0..0..2....0..0..2....0..0..2....0..0..2....0..0..2....0..0..2 %e A268047 ..0..1..1....2..1..2....0..2..0....0..0..2....1..2..0....0..1..1....2..1..2 %e A268047 ..1..0..0....0..2..1....0..3..1....0..2..3....0..3..0....0..3..3....1..3..1 %e A268047 ..0..1..1....3..1..0....0..1..0....2..0..0....0..0..3....1..2..2....2..0..0 %Y A268047 Cf. A268049. %K A268047 nonn %O A268047 1,1 %A A268047 _R. H. Hardin_, Jan 25 2016